The invention relates to a process for producing tubes, in particular for use in heat exchangers, from at least two metallic strips on a rolling mill train.
A production process and a rolling mill train are described in DE 10 2006 033 568 A1. The distances between the predetermined breaking points are determined according to the desired tube lengths. However, there are at least two, preferably even three separate strips. With respect to making the predetermined breaking points coincide, said application proposes that the speed of the strips be matched. When they are deformed to form the corresponding tube part, the strips are subjected to extreme loading, including tensile stresses, which may lead to changes in length in the strips. Since the strips are extremely thin, even temperature fluctuations presumably make themselves noticeable in that the distances between the predetermined breaking points are changed. This may result in tubes with predetermined breaking points that do not match at the ends, and this can lead to unusable tubes if certain permissible tolerances should be exceeded.